High threshold of total developmental quotient at 3 years for follow-up in extremely preterm infants

Aim

To investigate the relationship between the developmental quotient (DQ) at age 3 years and the need for educational support at school age in extremely preterm infants.

Methods

A total of 176 infants with a gestational age of <28 weeks were analyzed. The total DQ and subscales were evaluated using the Kyoto Scale of Psychological Development (KSPD) test. Neurodevelopment at age 3 years was stratified using total DQ in a conventional (DQ < 70 as developmental delay, DQ 70– <85 as subnormal, DQ ≥85 as normal) and a modified way (subdividing normal into DQ 85– <93 as low-normal and DQ ≥93 as high-normal). The prevalence of future educational support was compared for each stratum. Additionally, subscales were compared between those with and without educational support in each total DQ stratum.

Results

In conventional stratification, the prevalence of educational support was 32 (63 %) for developmental delay, 14 (24 %) for subnormal, and 10 (15 %) for normal. In modified stratification, the prevalence was 8 (26 %) for low-normal and 2 (5 %) for high-normal. While there was no significant difference in the odds of educational support between the normal and subnormal, the low-normal had significantly higher odds compared to the high-normal (OR 6.00; 95 % CI, 1.16–30.95, p = 0.03). Among the low-normal stratum, the language-social subscale was significantly lower in those with educational support.

Conclusion

Setting high thresholds for total DQ and evaluating detailed subscales at age 3 years may be useful for developmental follow-up in extremely preterm infants.